BS 6085:1981 download.Methods of test for Determination of the resistance of textiles to microbiological deterioration.
Section one. General
1. Scope
BS 6085 specifies methods of test for the determination of resistance of textiles to deterioration by the action of micro-organisms. Methods are also included for assessment of durability of resistance.
2. References
The titles of the standards publications referred to in this standard are listed on page 5.
3. Principle
Specimens are subjected to microbiological attack by soil burial, mixed inoculation on an agar plate or in a saturated atmosphere. The specimens are then examined visually and a subjective assessment of deterioration is made. Additionally, or alternatively, loss in performance caused by exposure is assessed.
4. Health and safety of operators
Since the procedures involve handling and working with micro-organisms, it is recommended that personnel trained in microbiology should perfärm those portions of the procedures involving the handling of organisms and inoculated specimens. Attention is also drawn to the general recommendations on personnel safety given in BS2O11 :Part2.2J.
5. Standard atmosphere for conditioning and testing textiles
Where required, use the standard atmosphere for conditioning and testing as defined in BS 1051, i.e. temperature 20 ± 2 °C, relative humidity 65 ±2 %.
6. Test specimens
6.1 Dimensions
6.1.1 Visual assessment. Fabric specimens shall be at least 20 mm x 20 mm. Yarn specimens shall be wound round a stainless steel or glass frame in order to give a surface area of approximately 20 mm x 20 mm.
6.12 Performance loss. Fabric specimens shall be
1 50 mm x 25 mm. For the soil burial test, yarn specimens
shall be 600 mm long and tied round a stainless steel or
glass frame in a single loop. For the agar plate test the
600 mm long specimens shall be formed into a coil so
that they fit the test container.
6.2 Number of specimens
6.2.1 Visual assessment. At least four fabric specimens or
four yarn specimens shall be used.
6.2.2 Performance loss. Specimens shall be taken at random from the laboratory bulk sample.
Five fabric specimens shall be taken with their longer side in the machine direction and five fabric specimens with their longer side in the cross direction.
Twenty yarn specimens shall be taken in equal portions from the packages in the laboratory bulk sample.
6.3 Number of sets of specimens. The number of sets of specimens of material under test and control cloth to be taken depends upon the particular tests being carried out. and whether these are carried out in conjunction with some form of durability assessment. For each of the following stages, one set is required and it is essential that the choice of tests is clarified in a performance or test specification.
The following variants of procedures are available for test materials. Similar requirements apply to the control cloth, with the exception of the ‘as received’, each variant requiring one set of specimens as specified in 6.2.1 and 6.2.2.
(a) As received, but after sterilization, as specified under each test.
(b) After durability procedures; possibly after each procedure in order to assess the effect of the procedure on the treated fabric.
Cc) After soil burial.
NOTE. Additional sets could be required for extended or shortened exposures.
(d) After agar plate without nutrient.
(e) After agar plate with nutrient.
(f) After saturated atmosphere.
(g) After (b) and (c).
(h) After (b) and (d).
Ci) After (b) and (a).
(j) After (b) and (f).
6.4 Pro-treatment. If required by the performance specification, subject all the specimens including the cotton control cloth, to a durability procedure. Some examples are given in appendix A.
Section two. Soil burial test
7. General
This procedure is generally considered to be the most severe exposure for textile products. Only those products that will come in direct contact with soil, such as sandbags, tarpaulins and tents, or which will be subject to severe exposure to micro-organisms, such as shoe liners.
If the strength loss method of assessment is used, the cotton control strips should show a strength loss of at least 80 %. If visual assessment only is used, they should show a grade of observed growth of not less than 4. If this is not the case repeat the test.
If the fabric under test is coated, test at least two specimens with the uncoated face uppermost and at least two specimens with the coated face uppermost.
Section four. Saturated atmosphere test
14. General
This procedure is used for evaluation of textiles that will not come into direct contact with fungi but may be contaminated with airborne spores. It can also be used for evaluating the efficiency of biocides. For this test visual assessment only is used.
1 5. Apparatus and reagents
15.1 Apparatus. The following apparatus is required.
15.1.1 Glass or plastics containers with fitting lids and free water exposed at all times in the base to maintain a relative humidity within it which is greater than 90 %. It shall be designed so that the specimen does not rest in the water and cannot be splashed by it. Kilner jars and French square bottles are suitable.
15.1.2 Incubator, as specified in 11.1 .1.
15.1.3 Plastics paperclips, or nylon thread to suspend the specimens.
15.2 Reagents. The following reagents are required
15.2.1 Mixed spore suspension, cultures as specified in 11.2.1 and prepared as in clause 12.
15.2.2 Ethanol, 70 % solution,
16. Procedure
Prepare the required number of specimens of the textile under test, and the cotton control cloth. (See clause 6.)
Using separate containers for the control cloth, add water to each container and, taking care to avoid splashing, hang the specimens over the water usng plastics paperclips or nylon thread.
NOTE. If required, sets of specimens from more than one textile under test may be tested in one container with only one set of specimens from the cotton control cloth, providing that thn different textiles under test are essentially of the same composition and have received similar finishing treatments.
Evenly spray both sides of the specimens with about 1 ml of the mixed spore suspension, place the lid on the container(s) and incubate for a minimum of 1 4 days, removing the lid from the container for a few seconds every seven days to ensure a regular supply of fresh oxygen to the growing mouId
Remove the specimens and assess them in accordance with 1 7.1 . The cotton control cloth specimens should show a grade of observed growth of not less than 4. If this is not the case, repeat the test.